Feverish and with his body ravaged by painful lesions from a drug-resistant “superbug,” a 12-year-old Brooklyn boy gave his mother a simple dying wish.

“Mommy, I’m OK. I want to go to school on Monday. I love you,” Omar Rivera told his mother.

Aileen Rivera related Omar’s dying words yesterday in announcing her intention to sue the city-run Kings County Hospital, where doctors mistook the deadly staph infection methicillin-resistant staphylococcus aureus, known as MRSA, for a common allergic reaction.

The $25 million notice of claim cites “incompetent, unskilled and improper” treatment at the Kings County emergency room from where Omar Rivera was sent home with the antihistamine Benadryl after showing up with a high fever and boils on his back – telltale signs of MRSA.

“They kept telling me they know what they are doing,” a tearful Aileen Rivera, 42, said of the ER docs working that evening. “I just want justice so that no other mother has to go through what I went through.”

Doctors at the hospital, who examined Omar on Oct. 12, “jumped to the conclusion” he was having an allergic reaction to the Motrin his pediatrician prescribed two days earlier, according to Rivera family attorney Paul Weitz. Omar, who’d been suffering from pus-oozing lesions for days, was sent home. He died on Oct. 14.

Lawyers for Rivera, who works as a school aide in The Bronx, filed the paperwork in Brooklyn Supreme Court.

Kings County Hospital declined to comment, citing the potential lawsuit, but repeated their statement of the last several days that Omar “presented with non-MRSA-related condition and was treated.”

Hospital spokeswoman Ana Marengo added the case is being reviewed internally. She refused to say if the physician who treated Omar or his supervisor are still on regular rotation.

At least four new cases of MRSA were made public yesterday – two at city schools and two at area colleges.

Meanwhile, the city Health Department said its hands are tied by the fact that MRSA is not a reportable disease and continued to urge New Yorkers to simply wash their hands.

“We are going to be seeing individual cases all the time because everyone has become aware of it, not because it’s an increase,” said a spokeswoman for city Health Commissioner Thomas Frieden. “[MRSA is] very common, very treatable.”

Individual cases of MRSA will not be investigated unless there is compelling reason to believe there is a cluster, such as the 10 players on an Iona College sports team who all contracted the superbug, the spokeswoman said.

Meanwhile, Sen. Richard Durbin (D-Ill.) will introduce a bill today that would make it mandatory for hospitals to report MRSA infection rates.